OK, let me cover the looks first. Outside. The car is VERY sensitive to colour. If you're going to buy one, look at one in the colour you're going to buy, not from the BMW brochure! Mines in metallic black and it looks great. The standard alloys are also horrid to look at and the 16-inch rims don't look right.
Inside, the seats (black leather in my case) are far better than the previous 5-series. They offer more support in all areas. The cabin is also more roomy, especially in the rear. What has gone backwards is the dashboard. It all works, I just don't really like it, which brings me on to...
I-Drive! I'm sold on it. You need to read the manual and sit on the drive for 30-minutes to "play" with it. But then is very easy to use. In honesty, once you have set-up all your preferences (door locking, light delays, steering wheel buttons...) you rarely touch most of it.
As with the outside, the inside is colour sensitive, and some of the combinations are horrid!
The build and quality of materials are excellent, better than the last model in just about every respect (except the headlight switch if I'm picky (I never use it as it's got auto headlights anyway!) ).
Driving the car is a joy. The 3-litre petrol engine and the 6-speed autobox work brilliantly together. It pulls hard at any speed. Changes up and down by the auto, in normal mode, are smooth and bearly noticeable. In sports mode, it's even swifter, but changes are a bit more noitceable. It has got the "manual" steptronic mode, but I never use it (unless very bored). The autobox simply does a better job than me.
On the economy side, around town it does 26mpg. On a recent 200-mile motorway run it did 32-mpg (at 85-mph). If you REALLY boot it, it will easily drop to the low 20's. I tried a Mercedes E-class before buying the 530, and it eats that alive in performance terms. I also tried a new Lexus GS300. That was smoother and quieter, but it could not match the BMW's engine for grunt.
The level of grip is also excellent, but it comes at a high price. The car is fitted with 18-inch rims (they look great) and run-flat tyres. These are the real downside of the car. They make the ride very hard (and I don't have the Sports Suspension) compared to the previous car. I can live with that. What I can't live with is that they make the car feel very nervous on the road. I think its due to the lack of flex in the tyre, it just makes it skip on white-lines, pot holes etc. that normal tyres flex and soak up. I'm sure it will grip and grip, it just doesn't feel like it. They are also very expensive to replace. I've been quoted £230 for a front and £250 for a rear (that's each!). I'm going to try to replace them with "normal" tyres and see if that improves things.
The only other disappointment is the SatNav (I have the business one). It does not have a fine enough level of granularity (ie complete postcode entry) and can pick some well strange routes if you have to vary off the planned route (farm tracks and 18-inch low profile tyres are not a good mix!).